A principle of the darkei (ways of) Hashem is that in order for the Am (Nation of) Yisroel to have maximum hashro’as hashechina (immersion in the Divine Presence), they must be separated with the maximum separation from the umos ha’olam (nations of the world). “Va’avdil eschem min ho’amim liheyos li — And I separated you from the nations to be Mine." So we see there’s a connection between the separating and the being Mine. — I Set You Apart (#546)